A data transmission using differential signals has been widely adopted in computers, telecommunication equipments, consumer electronics and the like. The differential signal uses one numeral value to represent difference between two physical quantities, and the differential signal, regardless of a data signal or a clock signal, adopts two signals, i.e. signal pair, with one signal representing positive and the other signal representing negative. When level of the positive differential signal is higher than that of the negative differential signal, the differential signal denotes logical “1”, and in the contrast, when the level of the negative differential signal is higher then that of the positive differential signal, the differential signal denotes logical “0”.
Nowadays, the differential signals used in data transmission primarily comprise a low voltage differential signal (LVDS), an inner system interface signal mini-low voltage differential signal (mini-LVDS) and a reduced swing differential signal (RSDS). With respect to the inner system interface signal, there are many other types of differential signal, such as point to point differential signal (PPDS), wise-BUS and the like.
In the prior art, when carrying out data transmission through the differential signals, data to be transmitted is converted to a differential signal directly and then is transmitted. In such case, if the number of bits for change between previous set of transmitted data and succeeding set of transmitted data exceeds a half of length of the data set, then the number of bit for change of the positive signal and negative signal amplitude of the differential signal would be more than the number of bit for non-changed. It can be observed in most of cases, during the data transmission, the more the changed bits is, the worse the electromagnetic interference is.